final on iron Flashcards
ferrous?
soluble
reduced form
Fe 2+
ferric?
oxidized
low soluability
Fe 3+
% hemoglobin in blood?
65%
% myoglobin in muscle?
10% its an O2 carrier
% enzymes catalase?
1-5%
5 factors affecting absorption?
dietary iron content (if low in iron the absorption rate increases)
bioavalibility of dietary iron ( nonheme)
amount of storage iron
physical status (disease or prego)
toxicity is more of a concern then deficiency
5 factors that enhance absorption?
animal protein (meat, fish, poultry)
vitamin C (nonheme turned into ferrous form)
fuctose
cysteine (amino acid, high bioavalibility)
low iron status
5 factors that inhibit absorption?
calcium and others compete for absorption
oxalate/phytate/fiber (bind to iron to raise excretion)
lack of stomach acid and dietary protein
coffee and tea
high iron store
how is it transported?
bind to transferrin to transport in the blood
needed for transport because its a defense system against oxidation and prevents use of free iron by bacteria
storage sites?
liver
spleen
bone marrow - RBC production
primary storage form?
ferritin
8 functions?
- oxygen transport as part of hemoglobin & myoglobin
- cofactor for enzymes
- normal brain and immune function
- globin = protein house for heme
- hemoglobin
- myoglobin
- cofacts for enzymes
- other enzymes
what hemoglobin does?
transports oxygen in the blood
Fe binds O2 where concentration is high
Fe releases O2 where concentration is low
its synthesized in RBC
what does myoglobin do?
transports O2 in muscle
function of cofactors for enzymes?
cytochromes : a,b,c
- ETC
- converts NADH and FADH2 into ATP
- detoxification of drug
other functions that require iron for the enzymes?
monooxygenases and dioxygenases
peroxidases
- catalase = antioxidant
- myeloperoxidase = production of OCL (radical) to kill backteria
- thyroperoxidase = thyroid hormone synthesis
deficiency without anemia?
depletion of bone marrow stores
decrease in serum ferritin and other markers of iron storage
hemoglobin still normal
deficiency symptoms?
behavioral disturbances impaired performance in cognitive tasks impairment of learning ability short attention span impaired immune system, decreased resistance to infection - T lymphocytes
deficiency anemia?
risk factor for disability and death
3-5% of females
not occur until severe iron depletion
histology: microcytic, hypochromic
iron deficiency anemia clinical symptoms?
fatigue palpitation rapid breathing decreased athletic performance inflammation on corner of mouth pica happens during pregnancy
populations at risk for deficiency?
- babies and young kids because of breast milk and growth spirts
- adolescents because girls start period and growing
- prego women in 3rd trimester
- chronic blood loss
supplementation?
beneficial to treat iron deficiency anemia
detrimental when taken in excess
- can be bad to intestinal cell, may lower copper and zinc and calcium, may be fatal to young children
no benefit or adverse effect on CHD
RDA recommendation for men and women?
UL?
men = 8 mg women = 18 mg UL = 45 mg
Sources?
clams beef forified foods shellfish liver oysters
toxicity?
accidental overload in young children
hemochromatosis
what is hemochromatosis?
genetic disorder of iron overload, single gene mutation
most common for whites around 20
what happens to the body with hemochromatosis?
short term
long term
short term
= fatigue, loss of apetite, memory loss
long term
= excess deposited in tissues creating organ failure
2 treatments for hemochromatosis?
phlebotomy / iron chelators
blood transfusion
toxicity symptoms?
and 4 stages
blood in vomit stage one = belly pain, diarrhea stage 2 = condition appears to improve stage 3 = body in swoll stage 4 = death
4 assessment of iron?
plasma ferritin = reflects storage status = <12 ug means deficient TIBC = >400 ug serum iron = <50 ug hemoglobin / hematocrit = hgb: < 12-13 g = hct: < 37-40% = late stage indicator
